Production of bulked yarn from thermoplastic high polymers



United States Patent 3,514,248 PRODUCTION OF BULKED YARN FROM THERMOPLASTIC HIGH POLYMERS Wolfgang Martin, Lucia Buechs, and Friedrich Wenger, Ludwigshafen (Rhine), Germany, assignors to Badische Anilin- & Soda-Fabrik Aktiengesellschaft, Ludwigshafen (Rhine), Germany No Drawing. Filed June 8, 1966, Ser. No. 556,017 Claims priority, application Germany, June 12, 1965, 1,289,240 Int. Cl. D06c 29/00 US. Cl. 8--115.5 6 Claims ABSTRACT OF THE DISCLOSURE Process for bulking a fibrous yarn or bundle of filaments of synthetic high molecular weight thermoplastic fiber-forming polymers, especially nylon 6 and nylon 66, by texturing to provide a durably or permanently crimped or textured bulk yarn, said process being improved by treatment of the fibrous yarn with a crosslinking agent, especially an aliphatic or isocyclic dialkylenediurea, and subjecting the treated yarn to a temperature of about 120 C. to 190 C.

It is known that bulked yarn of thermoplastic high polymers, for example polyamides, polyolefins, polyesters or polyacrylonitrile may be prepared by twisting yarn consisting of a plurality of filaments by means of a false-twist machine and setting the twist while the yarn is still hot. In the conventional crimping equipment the yarn coming from the supply package passes for example over a feed roller, then through a treatment zone in which it is subjected to a Wet treatment and/or a heat treatment, then through the twist head of the false-twist machine and finally to a delivery roller. The yarn is in a highly twisted condition shortly after leaving the feed roller and is untwisted again immediately after the twist head.

According to other prior art methods for the production of bulked yarn, crimping is effected by drawing the thread over a heated knife edge, by treatment in a stuifer box, or by using a jet of air.

The said methods for the manufacture of bulked yarn usually employ filaments which have been stretched to such an extent that they have a maximum breaking extension of to We have now found that bulked yarns or bundles of filaments of thermoplastic high polymers can be advantageously prepared by conventional texturing methods when the yarns or bundles of filaments are treated with crosslinking substances during or after texturing.

Crimped yarn or filaments prepared according to this invention have better mechanical properties, for example higher elasticity and a more permanent crimp than those prepared by prior art methods.

Texturing of the yarns or filaments is carried out by conventional texturing methods. These methods are described for example in the book by Berkeley L. Hathorne on Woven Stretch and Textured Fabrics, Interscience Publishers, New York, and in a work by H. U. Schmidlin Elastische Textilien, SVF-Fachorgan fiir Textilveredlung, 20th year, part 2, February 1965. Thus for example the yarn may be textured by the false-twist method, by drawing the fiber over a knife edge by crimping in a stutter "box, by using a jet of air, by twisting and winding 3,514,248 Patented May 26, 1970 up. Among these methods, the false-twist method and the stutter-box method occupy a special position for carrying out the method according to this invention.

The yarns or bundles of filaments may be treated with crosslinking substances during or after the texturing. The yarns or bundles of filaments are advantageously treated by passing them through a solution of dispersion of the crosslinking substance in water. This treatment may be carried out prior to texturing or after texturing. If the treatment of the yarns or bundles of filaments be carried out after texturing, the impregnated yarns 01' bundles of filaments should be heated to elevated temperatures for a short time. The temperature depends on the high polymer used and on the crosslinking substance. Polyamides, such as nylon 66, are advantageously heated for example for 0.5 to 10 seconds at temperatures of from to 190 C. In the case of ethylene glycol terephthalate polyesters the treatment is also carried out at from 120 to 190 C. for the same length of time.

The crosslinking substances may advantageously be used in solution or emulsion. The concentration depends on the rate at which the yarn or bundle of filaments is passed through the solution or emulsion and also on ab sorption of water or solution by the high polymer. The crosslinking substances are in general used in concentrations of 1 to 30% by weight.

Examples of suitable crosslinking substances are bifunctional or polyfunctional isocyanates, bi-functional or higher than bifunctional carboxylic acids, aliphatic or isocyclic dialkylenediureas, bifunctional or higher than bifunctional halogen compounds, such as chloral or trichloroacetic acid; these substances are soluble in conventional solvents. Solutions in water are particularly preferred.

Examples of suitable thermoplastic high polymers are polyamides, such as nylon 6 and nylon 66; and polyesters, such as ethylene glycol terephthalate polyesters. Polyolefines, such as polyethylene, polypropylene or polyacrylonitrile, may also be used.

A measure of the texturing effect is the crimp rigidity; it is expressed as a percentage and is determined as follows. When a bulked yarn is loaded with a weight of 0.002 g./den., it is extended to a length 1. When loaded with a weight of 0.2 g./den., the extension is to a length L. Crimp rigidity is the value expressed by:

The invention is illustrated by the following examples in which parts are by weight.

EXAMPLE 1 A l40-denier nylon 6 yarn having 24 filaments is twisted at a temperatureof C. on a false-twist machine (type KRZ 250 of Friedrich Uhde GmbH, Dortmund) at 4120 rpm. After the yarn has cooled, it is dipped for two seconds in a bath consisting of a 3% solution of 1,6- hexamethylenediethylenurea which is at 25 C. The yarn is then heated for three seconds at C. The crimped yarn has a crimp rigidity of 47.8%.

Yarn which has not been impregnated with the crosslinking substance, but which has otherwise been treated in the same way, has a crimp rigidity of only 40.2%.

EXAMPLE 2 90-denier nylon 66 yarn consisting of 26 filaments is twisted at a temperature of 225 C. on a false-twist ma- X 100 percent chine (as in Example 1) at 31-60 r.p.m. After the yarn has cooled it is treated in each case with a 3% aqueous solution of a crosslinking agent. This is carried out by passing the yarn for thirty seconds through the liquor. The yarns are then heated for three seconds at 200 C. The results are set out in Table 1:

TABLE 1 Crosslinking agent: Crimp rigidity in percent Without crosslinking agent 50 Chloral hydrate 67 Trichloroacetic acid 69 Citric acid 64 EXAMPLE 3 TABLE 2 Crosslinking agent: Crimp rigidity in percent Without crosslinking agent 8 Chloral hydrate Trichloroacetic acid 16 We claim:

1. In a process for bulking a fibrous yarn of a thermoplastic polymer selected from the group consisting of nylon 6 and nylon 66 by texturizing to provide a permanently textured bulky yarn, the improvement which comprises: treating said yarn with a solution or dispersion of 4 about 1 to 30% by weight of 1,6-hexamethylenediethy1- enurea as a cross-linking agent; and heating the treated yarn to a temperature of about C. to C. at a point of time not before the texturizing step.

2. A process as claimed in claim 1 wherein said yarn is treated with said 1,6-hexamethylenediethylenurea before the texturizing step and the treated yarn is heated to said temperature during the texturizing step.

3. A process as claimed in claim 1 wherein both the treatment of the yarn with said 1,6-hexamethylene-diethylenurea and the heating of the yarn take place after the texturizing step.

4. A process as claimed in claim 1 wherein an aqueous solution of said 1,6-hexamethylenediethylenurea is used to treat said yarn.

5. A process as claimed in claim 3 wherein said yarn is heated at about 120 C. to 190 C. for a period of about 0.5 to 10 seconds.

6. The permanently textured yarn produced by the process of claim 1.

References Cited UNITED STATES PATENTS 2,l77,637 10/1939 Coffman. 2,685,497 8/1954 Sammons et al. 2,895,288 7/1959 Yoo. 3,220,085 11/1965 Luno et al. 28-76 X FOREIGN PATENTS 278,994 5/ 1965 Australia.

MAYER WEINBLATT, Primary Examiner US. Cl. X.R. 

